Process for the production of dyed cellulosic textile materials with wet and dry wrinkle resistance



results in wrinkling of the garment during wear,

United States Patent "lice PROCESS FOR THE IIioDUcTIoN .OF DYED cELLULosIc TEXTILE MATERIALS WITH WET AND DRY WRINKLE RESISTANCE Terrence W. Fenner, Robert M. Reinhardt, and John D.

I A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughoutthe World for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America. This inventionrelates to the production of cellulosic textile materials which are dyed and have a high degree of resistance to wrinkling in both the wet and dry state. The treatment of cellulosic materials with formaldehyde by the traditional pad-dry-cure finishing process has been the subject of scientific investigation for almost half a century. The perfection of this process using formaldehyde is highly desirable because of the low cost of this reagent but has never been achieved for routine use on a commercial scale. The causes of the failures have been elusive. Among those frequently cited have been volatilization of the formaldehyde rather than reaction with the cellulose and extreme strength losses due to the strong catalysts required for the reaction.

Recently, a more practical approach to the problem of formaldehyde treatment of cotton has been reported by Reeves and coworkers in Textile Research Journal, vol. 30, No. 3, pp. 179192 .(March 1960). It was shown that by treating cotton fabric with an aqueous solution containing formaldehyde and a strong mineral acid as catalyst, products with high Wet wrinkle resistance were obtained. This treatment is carried out with cotton in the swollen state in the aqueous solution rather than in the collapsed state as in the dry curing step under dehydrating conditions in the pad-dry-cure process. How ever, these products had dry wrinkle resistance properties scarcely better than that of untreated cotton. It was further shown by Reeves and coworkers that the resulting dry Wrinkle resistance could be improved if a suificient portion of the water of the treating bath was re placed by a relatively nonswelling agent such as acetic acid, The use of large percentages of a relatively expensive reagent such as acetic acid makes recovery of this reagent necessary for reasonably economical operation ofthe process. A recovery system necessitates an added investment in equipment and in trained operating personnel not usually present in a textile finishing plant.

Further, because of the preference of the modern consumer for the comfort and convenience of wrinkle resistant wash-and-wear garments, to be successful commercially for this market, a fabric must have a high degree of both wet and dry Wrinkle resistance. A fabric with good wet wrinkle resistance but poor dry Wrinkle resistance has smooth drying properties when drip dried; that is, dried on a clothes line from the dripping Wet state, but is not satisfactory when tumble dried in an automatic dryer. Further, lack of good dry wrinkle resistance similar to that of untreated cotton. A garment fabricated from 3,130,001 Patented Apr. 21, 1964 textile materials, fiber, yarn, or fabric, which have been treated with formaldehydein the swollenstate. (For convenience in this specification, treatment of cotton in the swollen state with aqueous formaldehyde using strong mineral acid as catalyst, essentially as described by Reeves and coworkers, will be referred to as the wetformaldehyde treatment and the so-treated cotton will be referred to as Form W cottonf) This objective is accomplished by an added step to the wet-formaldehyde treatment. This step is carried out after the Form W cotton is washed free of'unused reactant and mineral acid catalyst. The textile material is dried or not dried,

as the processor desires, and then impregnated with an acidic catalyst material or material With latent acidic properties, dried at a low temperature, and baked at a higher temperature. This added step produces good dry wrinkle resistance with little or no decrease in the degree of Wet wrinkle resistance. The process of this invention may be carried out with the standard equipment found in the ordinary textile finishing plant and no recovery of expensive chemical reagents isnecessary.

Fabric treated by the process of this invention may be drip dried or tumble dried after laundering to produce a smooth appearance. They will be Wrinkle resistant while being worn and will maintain their smart-looking smooth appearance.

It is another object of this invention to provide a process for improvement of the dry wrinkle resistance of textiletmaterials which have been treated with other aldehydic crosslinking reagents in the swollen state similar Dye Uptake Fabric: 7 (mg. dye/g. fabric) Bleached cotton 1.68 Mercerized cotton -1 2.32

FormW cotton 2.71 Form W cotton-cat. impregnated and heat treated 0.91

, These data were obtained by determining the change in concentration of dye solutions (Solantine Blue 4GL) when used to dye accurately weighed samples of fabric under controlled conditions. Concentration of the dye solutions were determined by measurement of light transmission (600 mu) with a photoelectric colorimeter and comparison of the transmission with a previously prepared standard curve.

4 Cotton dyed prior to the wet-formaldehyde treatment maybe radically changed in its dyed appearance by the strong mineral acid which is required to catalyze the reaction of the aqueous formaldehyde solution and cellulose. These changes may range from only slight shade differences through major color changes to complete stripping of the color from the textile material. f

Thesedisadvantages couldprecludethe' production of anything but white fabric by the process of this invention. Itis a further object of this invention to provide a process for the production of dyed fabric with both 3 Wet and dry wrinkle resistance from cotton treated with formaldehyde in the swollen state.

This objective is accomplished by employing a specific sequence of events in the finishing and dyeing of the process of this invention. This sequence of events may be outlined thus:

(1) Treating cotton with aqueous formaldehyde containing strong mineral acid as catalyst.

(2) Washing the fabric free of unused reactant and catalyst.

(3) Drying the fabric, if desired.

(4) Dyeing the wet-formaldehyde treated fabric (which has increased dye receptivity) by any of the many techniques which are well-known to those skilled in the art.

(5) Washing the fabric free of unused dye and dyeassistants.

(6) Drying the fabric, if desired.

(7) Impregnating the fabric with an acidic or latent acid catalyst.

(8) Drying the fabric at low temperature.

(9) Heat treating the fabric at an elevated temperature.

(10) Washing the fabric.

(11) Drying the fabric.

By employing this sequence of events, cellulosic fabrics dyed to almost any color and shade may be produced with the comfort and convenience factors of resistance to wrinkling both in the dry and in the wet state. There is little or no change in the dyed appearance between fabrics after step 6 and step 11 of the sequence shown above. Slight differences which may be produced upon some dyes between step 6 and step 11, are of the same magnitude as the changes which take place with these dyes in resin-finishing dyed cottons with the conventional N-methylol type wrinkle resistance finishing agents.

Classes of dyestuffs which may be employed in this sequence of events include direct dyes, vat dyes, naphthol dyes, diazo dyes, and reactive dyes.

The process of this invention may be carried out by impregnating a wet-formaldehyde treated fabric, either undyed or which has been dyed after the wet-formaldehyde treatment, with a solution of an acidic actalyst material, for example, a mineral acid such as hydrochloric acid, sulfuric acid, and the like, an organic acid such as acetic acid, tartaric acid, citric acid, maleic acid, and the like, a material with latent acidic catalytic properties, for example, a metallic salt such as magnesium chloride, zinc nitrate, and the like, an ammonium salt such as ammonium chloride and the like, an amine hydrochloride such as 2-amino-2-methyl-l-propanol hydrochloride and the like, a combination metallic salt catalystmineral acid such as zinc nitrate-hydrochloric acid and the like, a combination metallic salt catalyst-organic acid such as zinc nitrate-acetic acid and the like, or a combination of metallic salts such as aluminum chloridemagnesium chloride and the like. The concentration of catalyst material used in the process of this invention may be varied from about 0.05% (weight percent based on the total weight of solution) to about 8%. Impregnation with the catalyst solution is generally carried out by immersing the fabric in the solution of the catalyst and squeezing the solution in to the fabric, as with pad rolls, centrifuges, and the like, to a wet pickup of about 60150%, based on the original weight of the fabric. A wet pickup of about 70-85% is preferred. Additives such as emulsified polyethylene, acrylic polymers, silicones, and the like may be used in the catalyst solution to effect further improvements in wrinkle resistance and in strength, abrasion resistance, and other wearing qualities.

Following the impregnation, the fabric is then dried at low temperature and then baked at a temperature of from about 100 C. to about 180 C. for a period of time of from about seconds to about 8 minutes which effects an increase in the dry wrinkle resistance of the fabric. Treatment at temperatures of from about C. to about 180 C. for periods of time of from about 30 seconds to about 8 minutes encompasses the preferred range for the baking step of the process of this invention, time and temperature being inversely adjusted. Alternatively, the drying and baking of the catalyst-impregnated fabric may be carried out in one operation.

After this step, the fabric may be neutralized or washed to free it from unused catalyst and/ or byproducts.

Having thus described the process of this invention in a general way, the following examples are meant to be illustrative of the invention but should not be considered as limiting thereon.

All percentages shown are percent by weight.

Dry crease recovery angles were determined by the procedure described in test method D1295-53T of the American Society for Testing Materials.

Wet crease recovery angles were determined by immersing the test samples in water until thoroughly wet, blotting the test samples, and then determining the crease recovery angle, in this state, by the same procedure as used for dry crease recovery angle.

The wash-wear rating scale of the American Association of Textile Chemists and Colorists, as described in Tentative Test Method 881958, American Dyestuff Reporter, vol. 47, No. 17, pp. P578-P580 (August 25, 1958), was used to evaluate appearance of samples after tumble drying.

EXAMPLE 1 A sample of 80 x 80 white cotton print cloth was mercerized with 20% sodium hydroxide solution and washed free of this reagent but not dried. The water wet fabric was impregnated with an aqueous solution containing 18.5% formaldehyde and 19.5% hydrochloric acid, passed through pad rolls to squeeze out excess solution, rolled, and allowed to stand for ten minutes. It was then washed free of reactant and catalyst, and dried. The fabric properties were: dry crease recovery angle (warp) 97; wet crease recovery angle (warp) 144; wash-wear rating after tumble drying 1; bound formaldehyde 1.60%.

EXAMPLE 2 EXAMPLE 3 A portion of the fabric from Example 1 was treated as in Example 2 except that no catalyst material was included in the solution. The dry wrinkle resistance was not improved as indicated by the wash-wear rating of 1 after tumble drying.

EXAMPLE 4 A portion of the fabric from Example 1 was padded to a wet pickup of about 80% with a solution containing 0.5% Zn(NO -6H O, 0.1% acetic acid. 1.5% emulsified polyethylene, and 0.1% fluorescent whitening agent, mounted on a pin frame at original dimensions, dried at 60 C. for 7 minutes, baked at C. for 4 minutes, washed, and dried. The fabric properties were: dry crease recovery angle (warp) 136; wash-wear ratingafter tumble drying 5.

EXAMPLE 5 Step A.-A sample of mercerized cotton 80 x 80 print cloth was impregnated with an aqueous solution containing 7.4% formaldehyde and 19.5% hydrochloric acid,

passed through pad rolls to squeeze out excess solution, rolled, allowed. to stand for ten minutes, thoroughly washed free of reactant and catalyst, and dried.

Step B.Samples of this wet-formaldehyde treated fabric were then impregnated with aqueous solutions of the catalysts listed in Table I, mounted on pin frames at original dimensions, driedat 60 C. for 7 minutes, baked at 160 C. for 4 minutes, Washed, and dried. The resulting properties of the fabrics are shown in Table I.

Table 1 Dry Wash- Crease Wear Bound Catalyst solution used in Step B of Recovery Rating Formal- Example Angle After dehyde, (Warp), Tumble percent degrees Drying None (result of Step A.) 95 I 2 0.05% Hydrochloric acid 126 4 0.05% Sulfuric acid- 123 4 1% Acetic acid 96 3 1% Citric acid 101 3 1% Maleic acid 118 4 1% Tartaric acid 113 3 0.1% Zinc nitrate hexaliy 90 3 0.25% Zinc nitrate hexahydrate 107 4 0.5% Zinc nitrate hexahydrate 117 4 1% Zinc nitrate hexahydrate 120 4 0.5% Magnesium chloride hexahydrate. 105 3 0.5% Zine nitrate hexahydrate0.05%

hydrochloric acid 132 4 0.5% Zinc nitrate hexahydrate 5% acetic acid 126 4 1% Ammonium chloride 124 4 1% 2-amino-2-methyl-1propanol hydrochloride 96 4 0.2% Aluminum chloride-7% magnesium chloride hexahydrate 130 4 EXAMPLE 6 Step A.Cotton print cloth was treated by the wetformaldehyde process similar to the procedure described in Example 1, so as to yield fabrics with various bound formaldehyde contents and thus various degrees. of wet and dry wrinkle resistance.

Step B.-The fabrics from Step A of this example were padded to a wet pickup of about 80% of a solution containing 0.5% Zn(NO 6H O and 0.05% acetic acid, mounted on pin frames at original dimensions, dried at 60 C. for 7 minutes, baked at 160 C. for 3 minutes, washed, and dried.

The properties of the fabrics after each step are shown in Table II.

Table II After Step A of Example 6 After Step B Dry Crease Wet Crease Dry Crease Wet Grease Bound Formalde- Recovery Recovery Recovery Recovery hyde, Percent Angle Angle Angle Angle (Warp), (Warp), (Warp), (Warp), degrees degrees degrees degrees EXAMPLE 7 Step A.-Cotton print cloth was treated by the wetformaldehyde process, similar to the procedure described in Example 1, so as to yield a fabric with 0.60% bound formaldehyde. The wet crease recovery angle T Table III Baking time D r 1 (at 160 0.); I 1y agisgg ggtgg 9 None (result of Step A) 82 30 seconds 107 1 minute -I 113 2 minutes 122 3 minutes 120 4 minutes 119 8 minutes 129 EXAMPLE 8 Samples of the fabric fromStep A of Example 7 were impregnated with a solution containing 0.5% a

Zn(NO '6H O and 0.5% acetic acid, padded to about wet pickup, mounted on pin frames at original dimensions, dried at 60 C. for 7 minutes, baked at various temperatures for 3 minutes, Washed, and dried. The results are shown in Table IV.

Table IV Baking temperature (for 3 minutes), deg. my ifff i figgg None (result of Step A, Example 7) 82 91 100 n 113 160 120 180 119 nated with an aqueous solution containing 12.5% glutaraldehyde and 18.5% hydrochloric acid, passed through pad rolls to squeeze out excess solution, rolled, allowed to stand for ten minutes, washed, and dried. The fabric properties were: dry crease recovery angle (warp) 85; wet crease recovery angle (warp) 125; weight add-on 1.7%.

Step B.A portion of this fabric was padded to about 80% wet pickup of a solution of 0.5% Zn(NO -6H O and 0.05 acetic acid, mounted on pin frames at original dimensions, dried at 60 C. for 7 minutes, baked at 160 C. for 3 minutes, washed and dried. The dry crease recovery angle (warp) was 103; wet crease recovery angle (warp) 123.

EXAMPLE 10 pin frame at original dimensions, dried at 60 C. for 7 (warp) of the fabric was dry crease recovery angle (warp) 82.

Step B.-Samples of the fabric from Step A of this example were impregnated with a solution containing 0.5% Zn(NO -6H O and 0.05% acetic acid, padded to mounted on pin frames at orig- C. for 7 minutes, baked at washed, and dried.

about 80% wet pickup, inal dimensions, dried at 60 C. for various periods of time, The results are shown in Table III.

minutes, baked at 160 C. for 3 minutes, washed, and dried; then dyed with Solantine Blue 4GL in a 1% dyeing.

using dye procedures recommended by their manufacturers (a 1% dyeing was used in each case, except a 3% dyeing was used with Naphthol AS-SW. and a 4% dyeing with Diazine Black OD); then Wet-formaldehyde treated asin Step A of Example 5; then impregnated with catalyst, dried, and heat-treated as in the corresponding step of sequence I of this example.

III. Wet-formaldehyde treated as in Step A of Example 5; then dyed as in the corresponding dyeing step of sequence 11 of this example; then impregnated with catalyst, dried, and heat-treated as in the corresponding step of sequence I of this example.

Samples dyed after the wet-formaldehyde treatment were dyed to a deeper shade than mercerized cotton similarly dyed. The fabric from sequence I of this example was dye resistant. Table V shows the results of the treatments.

II. Dyed with the various dyestuffs listed in Table V,

Table V Change in Ap- Color Index Number pearance oi Dyed Wash- Seqnence Fabric (Comparison Wear Dye Used Dye Class of Fabric at End Rating Finishing oi Processing With After and Appearance Im- Tumble Part I Part II Dyeing 1 mediately After Drying Dyeing) 2 Solantine Blue 4GL Direct Dir. Blue 78 34200 I Resist 5 D do II 3 III 1 5 II 4 4 0 III 2 4 Congo Red". II 4 4 Do III 2 5 Diazine Black OD III 0 5 Procion Brilliant Orange GS III 0 5 N aphthol AS-SW Azoic Coup. 7 37565 III 0 4 Ponsol Jade Green Supra D Vat Green 1 59825 II 2 4 0 do 59825 III 0 4 1 Sequence of events in dyeing-finishing process were: I. Wet-formaldehyde treated, impregnated with catalyst and heat treated, then dyed; II. Dyed,

aldehyde treated, dyed, then impregnated with catalyst and heat treated.

Rating scale: O-n0 change; 1s1ight change; 2-appreciable change; 3-cons1derable change; 4vcry great change.

We claim:

1. A process for producing a dyed cellulosic textile material that exhibits both wet wrinkle resistance and dry wrinkle resistance comprising the following steps carried out in sequence:

(a) treating a cellulosic textile material at room temperature and for at least 10 minutes with an aqueous solution containing from about 7.4% by weight to about 18.5 by weight of an aldehyde selected from the group consisting of formaldehyde and glutaraldehyde and from about 18.5% by weight to about 19.5% of hydrochloric acid as a catalyst;

(12) washing the aldehyde and acid treated product of step (a) free from unreacted aldehyde and acid with water;

(0) dyeing the washed product of step (b) with a cotton dye;

(d) washing the dyed product of step (0) free from dye reagents with water;

(e) impregnating the washed product of step (d) with an aqueous solution containing from 05% to 8.0% by weight of an acidic catalyst selected from the group consisting of a mineral acid, an organic acid, and a latent acid catalyst to a wet pickup of about from 60% to 150%, based on the original weight of the cellulosic textile material;

(7) drying the catalyst impregnated product of step (e) at a temperature of 60 Q;

(g) baking the dried product of step (f) at a temperature of about from 100 C. to 180 C. for periods of from eight minutes to seconds, the shorter time intervals being employed with the higher temperatures; and

(h) washing the dried and baked product of step (g) free from residual acidic catalyst with water.

wetformaldehyde treated, then impregnated with catalyst and heat treated; III. Wet-form- 2. The process of claim 1 wherein the aldehyde is 25 formaldehyde and the acidic catalyst is Zn(NO -6H O.

3. The process of claim 1 wherein the aldehyde is glutaraldehyde and the acidic catalyst is Zn(NO 6H O.

4. A process for producing a dyed cellulosic textile material that exhibits both wet wrinkle resistance and dry out in sequence:

(a) treating a cellulosic textile material with an aqueous solution containing an aldehyde selected from the group consisting of formaldehyde and glutaraldehyde and a strong mineral acid as a catalyst;

(b) removing unreacted aldehyde and acid from the aldehyde and acid treated product of step (a);

(c) dyeing the product of step (b) with a cotton dye;

(d) removing unreacted dye reagents from the dyed product of step (c);

(e) impregnating the product of step (d) with an aqueous solution containing from .05 to 8.0% by weight of an acidic catalyst to a wet pickup of about from to based on the original weight of the cellulosic textile material;

(7) drying the catalyst impregnated product of step (e) at a temperature not exceeding 60 C.;

(g) baking the dried product of step (1) at a temperature of about from 100 C. to C. for periods of from eight minutes to 30 seconds, the shorter time intervals being employed with the higher temperatures; and

(h) removing residual acidic catalyst from the dried and baked product of step (g).

Morton May 27, 1941 Schroeder Mar. 11, 1958 

4. A PROCESS FOR PRODUCING A DYED CELLULOSIC TEXTILE MATERIAL THAT EXHIBITS BOTH WET WRINKLE RESISTANCE AND DRY WRINKLE RESISTANCE COMPRISING THE FOLLOWING STEPS CARRED OUT IN SEQUENCE: (A) TREATING A CELLULOSIC TEXTILE MATERIAL WITH AN AQUEOU SOLUTION CONTAINING AN ALDEHYDE SELECTED FROM THE GROUP CONSISTING OF FORMALDEHYDE AND GLUTARALDEHYDE AND A STRONG MINERAL ACID AS A CATALYST; (B) REMOVING UNREACTED ALDEHYDE AND ACID FROM THE ALDEHYDE AND ACID TREATED TREATED PRODUCT OF STEP (A); (C) DYEING THE PRODUCT OF STEP (B) WITH A COTTON DYE; (D) REMOVING UNREACTED DYE REAGENTS FROM THE DYED PRODUCT OF STEP (C); (E) IMPREGNATING THE PRODUCT OF STEP (D) WITH AN AQUEOUS SOLUTION CONTAINING FROM .05% TO 8.0% BY WEIGHT OF AN ACIDIC CATALYST TO A WET PICKUP OF ABOUT FROM 60% TO 150%, BASED ON THE ORIGINAL WEIGHT OF THE CELLULOSIC TEXTILE MATERIAL; (F) DRYING THE CATALYST IMPREGNATED PRODUCT OF STEP (E) AT A TEMPERATURE NOT EXCEEDING 60*C.; (G) BAKING THE DRIED PRODUCT OF STEP (F) AT A TEMPERATURE OF ABOT FROM 100*C. TO 180*C. FOR PERIODS OF FROM EIGHT MINUTES TO 30 SECONDS, THE SHORTER TIME INTERVALS BEING EMPLOYED WITH THE HIGHER TEMPERATURES; AND (H) REMOVING RESIDUAL ACIDIC CATALYST FROM THE DRIED AND BAKED PRODUCT OF STEP (G). 